In the industrial machine and equipment manufacturing industries, parts and castings which are subject to machining must be cleaned to remove cuttings, oils, chips and other contaminants. In a like manner, in other industries, including the maintenance industry, items such as vehicle parts must be cleaned to remove tars, oils, chips and metallic particles as well as other debris before the parts can be reused or replaced.
Parts washing machines generally include a wash chamber where parts are contacted in stages first by a wash liquid and a then by rinse liquid. The washing and rinse stages typically include one or more forms of agitation, such as high-pressure liquid or vapor spray, parts rotation, and ultrasonics. The washing and rinse cycles of a parts washing machine may entail both a spraying step, where liquid is sprayed onto parts in an air environment, and an overflow step, where parts are fully submerged in liquid and then agitated by combinations of turbolators, rotation, ultrasonics, spraying, and the like.
Automated parts washers typically include a liquid recycle system for cost reduction and environmental protection. In a conventional design, the associated drainage system for recycling liquid includes separate wash liquid and rinse liquid tanks, each coupled to the wash chamber by separate drainage passageways and control valves. This configuration allows a machine control system to drain liquid from the wash chamber to either holding tank as needed. This conventional approach has several significant drawbacks, however. First, such drainage systems require complicated valve setups and elaborate piping to provide the separate drainage passageways. Second, such systems suffer from limited drainage rates, which are insufficient to effectively flush debris from the wash chamber into the drainage system. Third, liquid treatment chambers linked to conventional drainage systems require separate means to prevent or control wash chamber overflow. Also, the parts washers of conventional design require a relatively large "footprint" on the factory floor.
Accordingly, there remains a need for a drainage system in a parts washing machine that overcomes one or more of these drawbacks.